Well it's solved. Unfortunately I can only relate 2nd hand as to what the tuner found and his explanation as explained to me by my friend, so prepare for goddamn chinese whispers. Bike was freighted to the mysterious "guru" who isolated the problem (after checking some of the things above) by switching a tank from another bike he had in to my friend's and the bike ran smoothly - so something in the tank. This bit I can only do my best to describe but would appreciate a more accurate interpretation 'cos even looking at parts diagrams I can't see what he is talking about. Culprit was the fuel pressure regulator - OK, I know what they do. But the issue was that apparently there is a small threaded hole apparently on the reg that should be have a "blanking plate" in laymen's terms, for it to do it's job of maintaining pressure. This was missing (and could not be found in the tank). It was replaced and the bike is running fine. I can't guarantee I've got the discussion exactly right but it was to that effect. Anyone understand this or, really pushing the friendship, have a picture where this "plate" or maybe it's a plug I dunno, is showing. I just can't see anything like that in the parts catalogue. Thanks
yip, I get that. tho I cant see the specific pump in question I get how if it wasn't reaching pressure, probably around 2bar it wouldn't run correctly or not a tall.
